#ifndef MTL_ORIEN_H#define MTL_ORIEN_Hnamespace mtl {struct row_orien;struct column_orien;struct row_major;struct column_major;//: Row Orientation// This is used in matrix_implementation and in the indexer objects// to map (row,column) to (major,minor).struct row_orien {  template <int MM, int NN> struct dims { enum { M = MM, N = NN }; };  typedef row_tag orientation;  typedef row_major constructor_tag;  typedef column_orien transpose_type;  template <class Dim>  static typename Dim::size_type row(Dim d) { return d.first(); }  template <class Dim>  static typename Dim::size_type column(Dim d){ return d.second();}  template <class Dim>  static Dim map(Dim d) { return d; }};//: Column Orientation// This is used in matrix_implementation and in the indexer objects// to map (row,column) to (minor,major).struct column_orien {  template <int MM, int NN> struct dims { enum { M = NN, N = MM }; };  typedef column_tag orientation;  typedef row_orien transpose_type;  typedef column_major constructor_tag;  template <class Dim>  static typename Dim::size_type row(Dim d) { return d.second(); }  template <class Dim>  static typename Dim::size_type column(Dim d){ return d.first(); }#if 0  /* the static dim has already been transposed in matrix.h   so no need to do it here */  template <class Dim>  static typename Dim::transpose_type map(Dim d) { return d.transpose(); }#else  template <class Dim>  static Dim map(Dim d) { return Dim(d.second(), d.first()); }#endif};} /* namespace mtl */#endif /* MTL_ORIEN_H */